Mould replacement and method of mould replacement in a blow moulding apparatus

ABSTRACT

A moulding member defining a portion of a mould cavity for blow moulding an article in blow moulding apparatus, wherein said moulding member includes: (a) a backing member (5, 19) fixable to said blow moulding apparatus and having a wall which defines a recess in said backing member, and (b) a removable insert (3, 47) located in said recess and having a surface defining a portion of said mould cavity (11), wherein said backing member (5, 19) and said insert (3, 47) are located in register relative to each other by way of cooperating locating means (17, 73) on said insert and said backing member, respectively.

The present invention relates to moulding of articles, in particular itrelates to blow moulding apparatus, a novel moulding member and animproved method for mould replacement. It will be convenient to describethe invention with particular reference to blow moulding of containerssuch as thermoformable polymeric bottles, made for example frompolyethylene terephthalate ("PET") although it will be appreciated thatthe invention may have wider application.

In conventional blow moulding of thermoformable polymeric containers airis used to expand a heated preform against a female mould cavity. Themould cavity is formed by a number of mould parts, the number of mouldparts generally depending upon the complexity of the moulded container.The base configuration of the container may be formed from a singlemould element and the side walls may be formed from a pair of mouldhalves. In conventional container blow moulding apparatus the mouldhalves are each mounted directly to holding arms which reciprocallybring the mould halves together during the blowing phase and separatethe mould halves during the bottle ejection and preform loading phase.It may be desired to manufacture a variety of container shapes on oneblow moulding apparatus and for each particular container shape adifferent pair of mould halves and in some cases a different base mouldelement will be required to define the female mould cavity.

Every time a production run of one particular container shape finishesand a new container shape is to be made with a different side wallconfiguration or if mould halves become unacceptably worn, it isnecessary to remove the mould halves which are bolted to the holdingarms and to attach the new mould halves. The mould halves must then berealigned so that they index precisely to properly form the mould cavityand so that they do not damage each other during operation. Numerousretaining bolts are conventionally required to securely hold the mouldhalves to the holding arms and many of the bolts are difficult toaccess, particularly with multi-cavity moulding apparatus. Significanttime is taken up in accessing and removing these retaining bolts. Mouldhalves are generally heavy and awkward to hold when being repositionedand as a consequence, re-bolting of the mould halves may also takeconsiderable time.

Disconnection and reconnection of pipes and hoses to mould halves forheat transfer media, which may either cool or heat the mould half, willtake further time.

Furthermore, in conventional blow moulding apparatus there is limitedscope for adjustment of the holding arms so each mould half must beadjusted in its mounting to the holding arm by way of shims or the likewhich may often involve trial and error. This again can be timeconsuming. When combined, all the time consuming factors related tochanging mould halves can result in significant production down-time,especially when a blow moulding apparatus has a number of cavities to bereplaced. Due to the high speeds at which such blow moulding machinesoperate, correct alignment of mould elements is critical. With somebottle blow moulding machines having a capacity to produce about 20,000bottles per hour, this can easily translate to significant lostproduction--more so when more than one machine needs to have the mouldelements changed. Furthermore, once a pair of mould halves becomes wornunacceptably through use the entire mould halves must be replaced. Mouldhalves may be made from large amounts of metal and to replace the entiremould half can be an expensive exercise.

Accordingly, there is a need for a method of changing mould parts in ablow moulding apparatus to reduce production down-time assuring accuratealignment of substituted mould parts without the need to readjust theapparatus before recommencing production of containers.

It is an object of the invention to provide a solution to one or more ofthe problems of existing blow moulding apparatus.

According to the present invention there is provided a moulding memberdefining a portion of a mould cavity for blow moulding an article in ablow moulding apparatus, wherein said moulding member includes:

a) a backing member fixable to said blow moulding apparatus and having awall which defines a recess in said backing member; and

b) a removable insert located in said recess and having a surfacedefining a portion of said mould cavity,

wherein said backing member and said insert are located in registerrelative to each other by way of co-operating locating means on saidinsert and said backing member, respectively

and further including insert securing means being connectable to saidinsert and connectable to said backing member and said insert securingmeans being separate and remote from said cooperating locating means;wherein said insert and insert securing means are adapted to bedisconnected from the backing member so that they can both be removedtherefrom.

The co-operating locating means preferably consist of a projectingportion and a corresponding recessed portion whereby the projectingportion positively locates in the recessed portion. The projectingportion may be positioned on the inner wall of the backing member andthe corresponding recessed portion is thus positioned on an outersurface of the insert which is locatable in the recess. Alternativelythe projecting portion may be positioned on the outer surface of theinsert and the corresponding recessed portion is thus positioned on theinner wall of the backing member. In either case the projecting portionand the corresponding recess are of complementary dimensions such thatwhen so engaged the backing member and insert are located in register.This obviates the need to realign mould members in the blow mouldingapparatus when replacing one or more inserts as the backing membersshould previously have been aligned during previous blow mouldingoperations.

Preferably said projecting portion consists of a rib and said recessedportion consists of a corresponding groove although it will beappreciated that the projecting portion and recessed portion maycomprise a dowel and a corresponding bore, or some such similararrangement. More preferably the rib is positioned on and extendscircumferentially about the inner wall of the backing member and therecessed portion is positioned on the outer surface of the insert. Whenthe insert is positioned in the backing member, the inter-engagement ofthe co-operating locating means will thus prevent movement of thebacking member and insert relative to each other in at least onedirection, i.e. vertically, laterally or rotationally.

In a preferred embodiment where the plastics blow moulding apparatus isused to blow mould containers such as bottles there are provided twoopposing side wall forming moulding members and a separate base formingmould member, the sidewall forming mould members having removableinserts as defined above. The base forming mould member may beseparately changeable element or it may be a fixed element.

Preferably the insert has an outer surface which locates in the recessof the backing member and abuts the inner wall of the recess. It isdesirable to maximise the surface contact between the outer surface ofthe insert and the inner surface of the backing member in order tomaximise heat transfer between the backing member and the insert, theformer which may be heated or cooled by a heat transfer medium such aswater, so heat dispersion of heat is even and well maintained throughoutthe insert. Preferably the insert is in the form of a shell being madefrom the minimum amount of material necessary and is in intimate contactwith the respective backing member with minimal gap therebetween.

In a more preferred embodiment the co-operating locating means areconfigured such that when the insert and backing member are located inregister relative to each other the insert and backing member are alsosecured to each other by the co-operating primary corresponding locatingmeans. In other words the co-operating locating means is configured suchthat it locates and secures the insert and the backing together ratherthan simply locating them. In one embodiment the co-operating locatingmeans are slidably engageable members which may be positioned on theouter surface and the inner wall of the insert and backing respectively.

In a most preferred embodiment the co-operating locating means on theinsert and backing member are interlocking slidably engageable memberspreferably positioned on the outer surface of the insert and on theinner wall of the backing member. They may consist of a projectingportion having a chamfered face and a corresponding recessed portionwith a chamfered face of complementary dimensions such that the insert,when positioned in the recess in the backing member, is snug andprecisely located with minimal clearance between the outer surface ofthe insert and the inner surface of the backing. In this way the insertis held tightly in the backing member thus the backing member and insertcannot move to damage each other. By wedging the insert and backingmember together in this way facilitates good contact between the insertand backing member, which could otherwise result in poor moulding orinadequate thermal transfer between the insert and backing member. Inone embodiment the chamfered face in the form of a rib on the backingmember may be formed separately from the main body of the backing memberand fixed to form part of the backing member by way of suitable securingmeans such as bolts or screws. When there are two opposing mould membersused to blow mould the derived article such as a bottle, the recess inthe backing member is preferably semi-cylindrical. Therefore in thepreferred embodiment the groove in the insert and the rib on the recessare partially annular in shape and the mating surface of the insert andthe recess well of the backing member respectively.

There may further be provided secondary locating means for locating thebacking member and the insert. The secondary locating means may consistof a flange on the insert which is locatable in a secondary recess inthe backing member. The flange may have a projection having a chamferedface locatable in a corresponding groove in the secondary recess in thebacking member which also has a chamfered face such that the twochamfered faces wedge upon each other to secure and locate the flangeinto the groove in a similar fashion to the preferred embodiment of theco-operating locating means. The flange may be integral with the insert,or alternatively it may be separately detachable from the insert.

In this latter embodiment the flange must be capable of being fixed toboth the backing member and the insert simultaneously such that theinsert is secured to the backing member. In one embodiment the flangemay be in the form of a plate overlying a boundary between the insertand the backing member remote from the co-operating locating means. Inthis embodiment the flange may be separately connectable to the backingmember and insert by any suitable means such that upon disconnection ofthe flange from the backing member the insert and the flange cantogether be removed from the backing member.

In another embodiment the insert and the backing member may be locatedand secured together solely by the wedging action of the co-operatinglocating means and the secondary locating means. The wedging action maybe assisted by gravity when the weight of the insert causes the wedgingaction to keep the insert and backing member in place. There may furtherbe provided additional securing means such as a biasing means, forexample a spring or spring-loaded arm to urge the insert and backingmember into the wedging securement. The additional securing means may beone or more bolts or screws which force the insert and backing membertogether in the direction of slidable engagement of the chamfered faces.

In another aspect of the invention there is further provided insertsecuring means being connectable to said insert and connectable to saidbacking member and said insert securing means being separate and remotefrom said co-operating means; wherein the insert and insert securingmeans are adapted to be disconnected from the backing member so thatthey can both be removed therefrom. The insert securing means may beconnected to the backing member such that upon disconnection of theinsert securing means from the backing member the insert and insertsecuring means can both be removed at the same time. The insert securingmeans is preferably connected to the backing member such that upondisconnection of the insert securing means from the backing member theinsert and the insert securing means can both be removed therefrom. Theinsert securing means is optionally directly connected to the insert.For example it may be directly affixed to the insert by means of screwsor bolts. Alternatively the insert securing means may be indirectly orremotely connected to the insert, for example by virtue of the insertsecuring means direct connection or affixation to the backing member itmay become connected to the insert. The insert securing means mayalternatively be connected to the insert by providing a projectionadapted to engage within a recess in part of the wall of the insert orby any other connecting methods as are well known in the art.

The insert securing means may form part of the mould cavity if desiredand convenient, depending upon the configuration of the desired mouldcavity shape.

In another aspect of the invention there is provided an improved methodof mould replacement in a blow moulding apparatus comprising the stepsof:

(i) providing a moulding member defining a portion of a mould cavity forblow moulding an article wherein said moulding member includes

a) a backing member fixable to said blow moulding apparatus and having awall which defines a recess in said backing member, and

b) a removable insert located in said recess and having a surfacedefining a portion of said mould cavity,

wherein said backing member and insert are located in register relativeto each other by way of primary corresponding locating means on saidinsert and said backing member,

(ii) disengaging said primary corresponding locating means and removingsaid insert from said recess,

(iii) positioning a second insert having a surface defining a portion ofsaid mould cavity and having primary locating means corresponding tosaid locating means of said backing member, in said recess such thatsaid backing member and second insert are positioned in register witheach other.

In yet another aspect of the present invention there is provided animproved method of mould replacement in a blow moulding apparatuscomprising the steps of:

(i) providing a moulding member defining a portion of a mould cavity,said moulding member comprising:

a) a backing member fixed to said moulding apparatus; and

b) a removable insert having a surface defining said portion of saidmould cavity,

wherein said backing member and insert are positioned in registerrelative to each other by way of primary corresponding locating means onsaid backing member and insert and where said backing member and insertare independently connected by fixing means to a securing means;

(ii) disconnecting said fixing means to said backing member and removingtogether said insert and securing means; and

(iii) locating a new insert and new securing means in relation to saidbacking member about said primary locating means; and

(iv) fixing said new securing means to said backing means by said fixingmeans.

In a preferred embodiment moulding members defining the side walls of acontainer are changed in this way. A base forming mould member may ormay not also be changed.

It will now be convenient to describe the invention with respect to apreferred embodiment illustrated in the accompanying drawings. It is tobe understood that the drawings and the following description relate toa preferred embodiment only and are not intended to limit the scope ofthe invention.

In the drawings:

FIG. 1 is an elevation of a mould member of the present invention with abase mould element shown in cross-section.

FIG. 2 is a plan of an insert of the present invention.

FIG. 3 is an elevation of the insert of FIG. 2.

FIG. 4 is a plan of a flange of the present invention shown as aseparate element from the insert.

FIG. 5 is an elevation of the flange of FIG. 4 with the left hand sideof the flange shown partially in cross-section.

FIG. 6 is an elevation of a separate locating ring of one embodiment ofthe present invention with the left hand side shown partially incross-section along the line VI of FIG. 7.

FIG. 7 is a plan of the locating ring of FIG. 6.

In FIG. 1 mould member 1 consists of an insert 3, a backing member 5 anda base moulding structure collectively show as 7. Mould member 1 issubstantially semicircular in cross-section and has an identicalcounterpart (not shown) with which it cooperates to collectively definea mould cavity corresponding to the side walls of a blown container. Theneck finish of a preform is positioned adjacent neck portion 9 and thebody of the preform extends into cavity 11. Mould member 1 and itscounterpart are each connected to actuating arms of a blow mouldingapparatus (not shown) which move the mould members in a reciprocatingmanner between a closed position in which the mould members and basemoulding structure 7 form the complete mould cavity wherein thecontainer is blown, and an open position where the blown container canbe ejected and a new preform inserted.

Cavity 11 corresponds in shape to half of the side walls of thecontainer to be formed with surface 12 defining cavity 11. It will beappreciated that with different container configurations it may bepreferable to utilise different arrangements of mould members and ordifferent cavity configuration.

Backing member 5 has a semicircular inside surface 13 defining a recess.Insert 3 has a semicircular outside mating surface 15 which is dimensionto fit precisely against the inside surface 13.

Insert 3 has a chamfered projecting rim 17 which cooperates with asemicircular chamfered recess 19 in half-ring 21, which can more clearlybe seen in FIG. 6. Half ring 21 is bolted or otherwise secured tobacking member 5 by way of bolt holes 23, 25 and 27 so as to essentiallybecome integral with backing member 5. Half ring 21 has a semicircularupward projecting lip or rib 29 which forms undercut recess 19. Angledsurfaces 31 and 33 of insert 3 and half ring 21 respectively abut andpositively locate insert 3 and backing member 5 together in registerwhen insert 3 is placed against the inside surface 13.

It is preferable for the purposes of easy machining that half ring 21 bemade as a separate piece from backing member 5 and then bolted thereto,although the features of half-ring 21 may be made integrally withbacking member 5 if desired.

Insert 3 has on an upper surface 35 a plurality of bolt holes 41, 43 and45 to receive bolts which secure the half plate 47 to insert 3.

Turning to FIGS. 4 and 5 half plate 47 consists of a semicircular plateadapted to be separately connectable to insert 3 and backing member 5.Half plate 47 has a plurality of apertures 49, 51 and 53 for receivingbolts or similar fastening means to secure half plate 47 to insert 3 atcorresponding bolt holes 41, 43 and 45. Half plate 47 also has dowellocating holes 59 and 63 37 and 39 to align half plate 47 with dowels(not shown) in backing member 5 Half plate 47 additionally has aperture61 adapted to receive a bolt or the like to secure half plate 47 tobacking member 5. Half plate 47 has a neck ring locating recess 65adapted to receive the neck ring of a preform. On the radial peripheryof half plate 47 on the surface 67 adapted to abut upper surface 35there is a downwardly projecting lip 69 having a chamfered insidesurface 71 which positively locates in a corresponding recess 73 inbacking member 5 such that half plate 47 and backing member 5 arealigned upon assembly.

According to the process of the present invention, after a productionrun of a particular container shape has been completed and a newcontainer shape is to be manufactured the moulding apparatus is stoppedand advanced until a set of mould member are in an open position. Wherea new sidewall configuration is to be employed each mould half making upthe sidewalls of the blown container must be replaced. The process ofreplacing each mould half is identical so it is not important whichmould half is changed first.

First the securing bolt attaching the half plate 47 to the backingmember 5 through bolt hole 61 is removed. The half plate 47 and insert 3may then be removed upwardly out of engagement with the recess 19 and73. A substitute insert with the new cavity shape is then simplypositioned into the backing members and bottled thereto, with thechamfered projecting rim of the new insert locating in the recess 19 andthe projecting lip 69 of the half plate (which is identical to the halfplate which has been removed) locating in recess 73 so that the newinsert is positioned precisely in register with the backing member 5.The securing bolts are then positioned to fix the half plate to thebacking member 5. The same procedure is then followed for thecorresponding mould half and for the remaining mould cavities on theapparatus. As the backing members of both mould halves have previouslybeen aligned with each other, it is not necessary for any furtheradjustment to take place and production may commence once all thenecessary mould elements have been replaced.

If a mould insert becomes worn unacceptably it may be removed from thehalf plate simply by being unbolted. When being machined, the dimensionsof the interchangeable mould inserts and half plates must be strictlycontrolled so that they fit precisely with the backing members.

The components described above may be made from any suitable materialsknown in the art, and may be made by any suitable process provided thatthe necessary tolerances are complied with. The half plate may be madefrom steel or some other relatively hard wearing metal whereas theinsert may be made from a softer metal such as aluminium. It will beappreciated however that in one embodiment of the invention the insertand half plate may be integral. The invention may be utilised in bothsingle stage and two stage blow moulding and may be utilised indifferent types of blow moulding such as stretch blow, moulding orextrusion blow moulding, as will be appreciated by those skilled in theart.

It is to be understood that various modifications, additions oralterations may be made to the arrangements previously described withoutdeparting from the ambit of the present invention.

I claim:
 1. A moulding member defining a portion of a mould cavity forblow moulding an article in a blow moulding apparatus, wherein saidmoulding member includes:a) a backing member fixable to said blowmoulding apparatus and having a wall which defines a recess in saidbacking member; and b) a removable insert located in said recess andhaving a surface defining a portion of said mould cavity, wherein saidbacking member and said insert are located in register relative to eachother by way of co-operating locating members on said insert and saidbacking member, respectively and further including an insert securingmember being connectable to said insert and connectable to said backingmember and said insert securing member being separate and remote fromsaid cooperating locating members; wherein said insert securing membercomprises a plate overlying the boundary between the insert and thebacking member; and wherein said insert and insert securing member areadapted to be disconnected from the backing member so that they can bothbe removed therefrom.
 2. A moulding member according to claim 1 whereinsaid co-operating locating members consist of at least one projectingportion on either of the inner wall of the backing member or on theouter surface of the insert and a corresponding recessed portion on theother of the outer surface of the insert or the inner wall of thebacking member such that said projecting portion positively locates insaid recess portion.
 3. A moulding member according to claim 2 whereinsaid projecting portion consists of a rib and said recess portionconsists of a corresponding groove.
 4. A moulding member according toany one of claims 2 to 3 wherein said projecting portion is positionedon said inner wall of said backing member and extends circumferentiallyabout said inner wall and said recessed portion is positioned on theouter surface of the insert.
 5. A moulding member according to claim 1wherein said co-operating locating members are configured such that whensaid insert and said backing member are located in register relative toeach other said insert and backing member are secured to each other bysaid co-operating locating members.
 6. A moulding member according toclaim 1 wherein said co-operating locating members comprise interlockingslidably engageable members on said backing member and said insert.
 7. Amoulding member according to claim 6 wherein said interlocking slidablyengageable members comprise a projecting portion and a recessed portioneach having a chamfered face such that when said insert and backingmember are engaged said chamfered faces wedge upon each other to securesaid insert and backing member together.
 8. A moulding member defining aportion of a mould cavity for blow moulding an article in a blowmoulding apparatus, wherein said moulding member includes:a) a backingmember fixable to said blow moulding apparatus and having a wall whichdefines a recess in said backing member; and b) a removable insertlocated in said recess and having a surface defining a portion of saidmould cavity, wherein said backing member and said insert are located inregister relative to each other by way of co-operating locating memberson said insert and said backing member, respectively and furtherincluding an insert securing member being connectable to said insert andconnectable to said backing member and said insert securing member beingseparate and remote from said cooperating locating members; the insertsecuring member including a flange provided with a secondary locatingmember for locating in a recess in said backing member; and wherein saidinsert and insert securing member are adapted to be disconnected fromthe backing member so that they can both be removed therefrom.
 9. Amoulding member according to claim 8 wherein said flange secures saidinsert within said backing member by way of a projection on said flangewhich has a chamfered face located within a corresponding groove in saidbacking member having a chamfered face such that said chamfered faceswedge upon each other to secure and locate said flange into said groove.10. A moulding member according to any one of claims 8 to 9 wherein saidinsert and backing member are located and secured together solely bysaid co-operating locating members and secondary locating member.
 11. Amoulding member according to claim 1 wherein said insert securing memberis connected to said backing member such that upon disconnection of saidinsert securing member from said backing member the insert and insertsecuring member can both be removed therefrom.
 12. A moulding memberaccording to claim 1 wherein said insert securing member is directlyconnected to said backing member.
 13. A moulding member according toclaim 8 wherein said insert securing member comprises a plate overlyingthe boundary between the insert and the backing member.
 14. A mouldingmember defining a portion of a mould cavity for blow moulding an articlein a blow moulding apparatus, wherein said moulding member includes:a) abacking member fixable to said blow moulding apparatus and having a wallwhich defines a recess in said backing member; and b) a removable insertlocated in said recess and having a surface defining a portion of saidmould cavity, wherein said backing member and said insert are located inregister relative to each other by way of co-operating locating memberson said insert and said backing member, respectively and furtherincluding an insert securing member being connectable to said insert andconnectable to said backing member and said insert securing member beingseparate and remote from said cooperating locating members; wherein saidinsert securing member is fixed to said backing member by one or morescrews or bolts; and wherein said insert and insert securing member areadapted to be disconnected from the backing member so that they can bothbe removed therefrom.
 15. A blow moulding apparatus including aplurality of mould members movable in a reciprocating manner between aclosed position in which said mould members collectively define a mouldcavity for blow moulding an article and an open position for ejecting amoulded article and receiving a preform, wherein one or more of saidmoulding members consist of a moulding member according to claim
 1. 16.A moulding member defining a portion of a mould cavity for blow mouldingan article in a blow moulding apparatus, said moulding membercomprising:a) a backing member fixed to said moulding apparatus; and b)a removable insert having surface defining a portion of said mouldcavity, wherein said backing member and insert are positioned inregister relatively to each other by way of co-operating locatingmembers on said insert and said backing member, and further including aninsert securing member to connect said insert and backing member, saidinsert securing member comprising a plate overlying the boundary betweenthe insert and the backing member, said insert securing member beingconnectable to said insert and connectable to said backing member andsaid insert securing member being separate and remote from saidco-operating locating members and capable of being connected to both thebacking member and insert simultaneously such that the insert is securedto the backing member; wherein the insert and insert securing member areadapted to be disconnected from the backing member so that they can bothbe removed therefrom.
 17. A moulding member according to claim 16wherein said insert securing member is connected to said backing membersuch that upon disconnection of said insert securing member from saidbacking member the insert and insert securing member can both be removedtherefrom.
 18. A moulding member according to claim 17 wherein saidinsert securing member is directly connected to said backing member. 19.A moulding member defining a portion of a mould cavity for blow mouldingan article in a blow moulding apparatus, said moulding membercomprising:a) a backing member fixed to said moulding apparatus; and b)a removable insert having surface defining a portion of said mouldcavity, wherein said backing member and insert are positioned inregister relatively to each other by way of co-operating locatingmembers on said insert and said backing member, and further including aninsert securing member to connect said insert and backing member, saidinsert securing member being connectable to said insert and connectableto said backing member, wherein said insert securing member is fixed tosaid backing member by one or more screws or bolts, and said insertsecuring member being separate and remote from said co-operatinglocating members and capable of being connected to both the backingmember and insert simultaneously such that the insert is secured to thebacking member; wherein the insert and insert securing means are adaptedto be disconnected from the backing member so that they can both beremoved therefrom.
 20. A blow moulding apparatus including a pluralityof mould members movable in a reciprocating manner between a closedposition in which said mould members collectively define a mould cavityfor blow moulding an article and an open position for ejecting a mouldedarticle and inserting a preform wherein one or more of said mouldingmember consists of a moulding member according to claim
 16. 21. Amoulding member defining a portion of a mould cavity for blow mouldingan article in a blow moulding apparatus wherein said moulding membercomprises:a) a backing member fixed to said moulding apparatus; and b) aremovable insert having a surface defining a portion of said mouldcavity,wherein said backing member and insert are positioned in registerrelatively to each other by way of co-operating locating members on saidinsert and said backing member, and further including an insert securingmember which can be directly connected to said backing member and canalso be connected to said insert independent of said connection to saidbacking member, said insert securing member being remote from saidco-operating locating members and where upon disconnection of saidinsert securing member from said backing member said insert and saidinsert securing member can be removed from said backing member whilstsaid insert and insert securing member are still connected.
 22. Amoulding member according to claim 21 where the insert and the backingmember are urged into register by way of said locating members when saidinsert is secured to said backing member by said insert securing member.23. A moulding member according to either one of claims 21 or 22 whereinsaid insert securing member and said backing member include secondarylocating members to bring said insert and backing member into register.24. A moulding member according to claim 21 wherein said primarylocating members consist of interlocking semi annular chamfered flangesof complementary dimensions.
 25. A moulding member according to claim 21wherein said secondary locating members consist of interlockingchamfered members of complimentary dimensions.
 26. A blow mouldingapparatus including a plurality of mould members movable in areciprocating manner between a closed position in which said mouldmembers collectively define a mould cavity for blow moulding an articleand an open position for ejecting a moulded article and inserting apreform wherein one or more of said moulding member consists of amoulding member according to claim
 21. 27. A method of mould replacementin a blow moulding apparatus comprising the steps of:(i) providing amoulding member defining a portion of a mould cavity, said mouldingmember comprising:a) a backing member fixed to said moulding apparatus;and b) a removable insert having a surface defining said portion of saidmould cavity, wherein said backing member and insert are positioned inregister relative to each other by way of primary corresponding locatingmembers on said backing member and insert and where said backing memberand insert are independently connected by a fixing member to a securingmember; (ii) disconnecting said fixing member to said backing member andremoving together said insert and securing member; and (iii) locating anew insert and new securing member in relation to said backing memberabout said primary locating members; and (iv) fixing said new securingmember to said backing member by said fixing member.